The present invention relates to a catalyst for use in the hydrotreatment, hydrodemetallization and hydrocracking of heavy hydrocarbon feedstocks containing high levels of vanadium, nickel and sulfur and a method for the preparation of the catalyst.
Heavy crudes and residuals are generally defined as hydrocarbon feeds which contain high amounts of vanadium, nickel and sulfur. During the hydrotreatment of feedstocks having high concentrations of vanadium and nickel, the catalysts used in the treatment quickly accumulate these metals into their pores thereby resulting in a short catalyst life.
In order to increase the catalyst life the prior art has developed certain hydrotreatment catalysts which have an increased life expectancy. U.S. Pat. Nos. 4,152,250 and 4,196,102 disclose a process for removing metals from hydrocarbons employing clay catalysts of magnesium silicate having a double chain-type structure of the sepiolites type. These particular catalysts exhibit an increase in activity over conventional hydrotreatment catalysts. U.S. Pat. Nos. 3,118,845, 4,152,250, 4,196,102, Japanese Pat. No. 31,878/1974 and British Pat. No. 1,218,080 disclose the addition of a second component to a solid oxide catalyst in order to improve the porosity and activity of the final catalyst. U.S. Pat. Nos. 4,439,312 and 4,367,164 disclose a process and catalysts for treating heavy feedstocks using sepiolites and mixtures thereof with oxide forming substances. While these catalysts exhibit some increase in catalytic activity they still exhibit a short life cycle when treating heavy feedstocks when compared to the treatment of light feedstocks.
Naturally, it would be highly desirable to provide a catalyst and method for making same for hydrotreating, demetallizing and hydrocracking heavy hydrocarbon feedstocks wherein the catalyst is inexpensive to manufacture and exhibits a high accumulation capacity for vanadium, nickel and sulfur.
Accordingly, it is a principal object of the present invention to provide an improved catalyst for use in the hydrotreatment, hydrodemetallization and hydrocracking of heavy hydrocarbon feedstocks.
It is a particular object of the present invention to provide an improved catalyst as aforesaid which is manufactured from a naturally occurring material and thus is inexpensive.
It is a further object of the present invention to provide a method for preparing the catalyst as aforesaid.
Further objects and advantages will appear hereinbelow.